All 15 positive tests were for stimulants and a result of out-of-competition testing, with no positive match-day results.

There are now four players on two strikes, with one returning a second positive test in 2013.

Harcourt said that the results mirrored the increased use of such drugs in society. There had been a shift away from cannabis, with stimulants the drugs of choice, he said.

"The problems we're confronting really reflect players socialising, and if anything the use and acceptance of illicit drugs in the community at the moment is going up," Harcourt said.

"I don't take any comfort from the fact that the numbers have gone down."

The AFL increased the number of tests from the previous year.

Harcourt said he found that the players who had tested positive had done so during a night out drinking.

"Almost always," he said.

"It's guys going out, usually when they go home and catch up with friends and they have a few drinks and their guard starts dropping.

"They have a few more drinks and they use an illicit substance in a situation where their judgment is impaired."

The AFL's general manager of football operations, Mark Evans, said the IDP was delivering on its objective to treat the use of illicit substances as a health issue.

"The detections last year mean that 15 players have been subject to early intervention in the form of expert counselling, treatment and ongoing monitoring under this medical and welfare-based policy approach," Evans said.

"Illicit drug use is a significant issue across the broader community and the AFL playing group largely falls within the high risk 18-30 male age group. Individual players are not immune to peer group pressure and poor decision-making, but under this policy they have ready access to expert support and treatment to overcome the potential health impacts.

"Significantly, our advice is that the rate of illicit drug use within the AFL playing group remains substantially lower compared with the same age group of young men in the wider community."